Filtering

Filtering

RadAutoCompleteBox control provides implicit server-side filtering functionality, loading the drop-down items on demand.Once the user starts typing in the input area of the control, a request for new items is made to the server. The items are fetched from the server based on the value set to the Filter property.

There are two filtering options available:

• Contains - Filters all items which Text value contains the searched text as a substring.

• StartsWith - Filters all items which Text value starts with the searched text.

The default value of Filter property is Contains .

As of Q3 2013 release, we had introduced two properties - MinFilterLength and MaxResultCount:

• MinFilterLength - Sets the minimum length of the typed text before the control initiates a request for its DataSource.

• MaxResultCount - Sets how many results will the RadAutoCompleteBox be populated with.When this property is set, a "Show All Results" button appears at the bottom of the dropdown. Clicking this button will load all corresponding results.

When a WebService binding scenario is implemented and you need to use the "Show All Results" button and manage its visibility, the following requirements needs to be met:

• MaxResultCount should be set to a desirable value.

• A custom calculation in the WebService needs to be implemented, so you could check if the "Show All Results" button needs to be visible. For example, if the entries count returned from the data source match the MaxResultCount value - the "Show All "Results" should not be visible. In this case you could toggle its Visible state by simply setting EndOfItems property of the AutoCompleteBoxData object in the following manner:

AutoCompleteBoxData data = new AutoCompleteBoxData();
data.EndOfItems = true;

Dim data As New AutoCompleteBoxData()
data.EndOfItems = True

In cases when MaxResultCount property is used in RadAutoCompleteBox and the DataSourceSelect event is handled manually in order for Show All Results button to appear correctly, we recommend that the amount of items that will be selected should be at least with one item greater than MaxResultCount .

Both properties could be very useful in a heavy-data scenario. Controlling the MinFilterLength, could give you the ability to perform a search in your database, regarding the sequence of the typed characters. If the result is still potentially large, you could use the MaxResultCount, in order to return the first 100 results for example.